In telecommunication, one or more base station communicates with mobile stations such as mobile phones and laptops. Typically, a mobile station is modelled by a so-called cluster of local scatterers. This cluster is a collection of scatterers which are close to the transmitting mobile station, where the term “close” shall be interpreted as a distance which corresponds to a time which is much smaller than the symbol time. The scatterers constituting a cluster will, as their numbers grow, create a signal distribution, here termed azimuth spread.
A receiving base station will receive signals from scatterers, producing angular dependent distributions of signals. Typically, such a distribution is termed Power Azimuth Spread (PAS). A specific direction may, for example, be comprised of disturbing signals, producing an angular dependent distribution of the transmitted signals.
This results in a general problem with interference in a wireless multi-user communication system. The interference often limits the capacity of the system. There exists several well-known ways to handle interference, for example by using beam-forming.
However, beam-forming is mainly dealing with focusing a gain function in a certain direction. This function is derived subject to a direction, in which some desired signal is presumed to be. An interfering signal may lay in a close neighborhood (azimuth) to the desired signal, causing problems.
There is thus a need for reducing such interference without the disadvantages of prior art solutions. To achieve this, a simple and effective way to analyze the channel is needed.